Home > Articles

This chapter is from the book

Using Menus and MDI Forms

One of the worst interfaces ever created was the Menu Editor in Visual Basic 6 and earlier. It was a top complaint of developers; Microsoft heard their screams and provided an amazing, easy-to-use Menu Editor in Windows Forms. In addition to the editor being great, because items added to a menu are derived from a Menu class, you can easily create menu items dynamically at runtime, which was almost possible in Visual Basic 6. To test the new Menu Editor's features, you're going to create a Multiple Document Interface (MDI) application. The flexibility of MDI applications in .NET has also improved dramatically, as you'll see when you're done with the following exercise.

NOTE

The HelloNET application has been a SDI (single document interface) application until now. That means each form in the application is its own container. An MDI application has a parent form that contains children, and the child forms can't leave the screen boundary of the parent. MDI applications used to be the most popular type of UI, but in recent years SDI applications and Explorer-style applications have become more popular. Microsoft drives the UI trends with each new release of any product. Consider Microsoft Outlook: The Outlook Bar–style spread like wildfire when it was introduced, and it can be seen in hundreds of third-party applications today.

To get started, add three new forms to the HelloNET application by right-clicking the HelloNET project name in the Solution Explorer and selecting Add, New Windows Form. Name the new forms as follows:

  • parentForm

  • child1

  • child2

You'll notice that there is no MDI form template. This is now just a property on a form. After the three new forms are added, your Solution Explorer should look something like Figure 3.11.

Figure 3.11Figure 3.11 The HelloNET application after adding three new forms.

From the Solution Explorer, double-click the parentForm form so that it's in the Forms Designer. In the Properties window, change the IsMdiContainer property to True. You'll notice that the form now has a dark gray background color, which is the indication that it's a MDI parent form.

Next, drag a MainMenu control from the Toolbox to the form. The MainMenu control is a nonvisual control, which means it doesn't appear as part of the form. When nonvisual controls are added to a form, the screen splits and the controls are added to the bottom portion of the Forms Designer. This makes it very easy to see what nonvisual controls have been added to a form. At this point, your application should look something like Figure 3.12.

Figure 3.12Figure 3.12 The parentForm after adding a MainMenu control.

Adding menu items to the MainMenu is very intuitive: You simply type the name that you want the menu to display, and it shows up. Notice that you can go as many levels deep into a menu as you want—you just keep typing where the arrow is in the editor, and that's where the menu item appears. Use the up-, down-, right-, and left-arrow keys on your keyboard to navigate the menu levels. Figure 3.13 demonstrates the addition of items to a MainMenu.

Figure 3.13Figure 3.13 Adding items to a MainMenu.

Add the following five menu items to the MainMenu control:

  • Top Level Menu—&File

  • Sub Level 1—&Show child1, Name = showChild1

  • Sub Level 2—&Show child2, Name = showChild2

  • Sub Level 3—&Forms Count, Name = formsCount

  • Sub Level 4—&Close All Forms, Name = exitApplication

While adding items to the menu, you can right-click on the menu itself to get the contextual menu with available options for the MainMenu control. One of the most useful items is the EditNames toggle. If you click EditNames, you can change the name of the menu item directly from the Menu Editor. You can also do this via the Properties window. From the Properties window, some of the individual properties that can be set are the Shortcut, RadioCheck, and Visible properties.

NOTE

In the code you just added to create the menu items, an ampersand was placed in front of each of the menu item captions. The ampersand will place an underscore underneath the character it prefixes in the menu, and will allow the end user to use the ALT key in combination with the underlined character as a shortcut to the menu item.

After you've added the new menu items, you'll add some code that brings up the child1 and child2 forms, gets a count of open forms, and exits the application.

To do this, add the code in Listing 3.5 to the click events for their corresponding controls.

Listing 3.5 The Code-Behind for the MDI Application

VB.NET

Private Sub MenuItem2_Click(ByVal sender As System.Object, _
  ByVal e As System.EventArgs) Handles showChild1.Click

   Dim f As New child1()
   f.MdiParent = Me
   f.Show()

  End Sub

Private Sub showChild2_Click(ByVal sender As System.Object, _
  ByVal e As System.EventArgs) Handles showChild2.Click

   Dim f As New child2()
   f.MdiParent = Me
   f.Show()

  End Sub

Private Sub formsCount_Click(ByVal sender As System.Object, _
  ByVal e As System.EventArgs) Handles formsCount.Click

   ' Get the number of children
   MessageBox.Show(Me.MdiChildren.Length)

   ' Declare a Form object to get object properties
   Dim f As Form
   For Each f In Me.MdiChildren
     MessageBox.Show(f.Name.ToString)
   Next

End Sub

Private Sub closeAllForms_Click(ByVal sender As System.Object, _
   ByVal e As System.EventArgs) Handles closeAllForms.Click

   ' Declare a Form object and call the Close event
   Dim f As Form
   For Each f In Me.MdiChildren
     f.Close()
   Next

End Sub

Private Sub exitApplication_Click(ByVal sender As System.Object, _
   ByVal e As System.EventArgs) Handles exitApplication.Click

   ' Exit the Application
   Application.Exit()

End Sub

C#

private void showChild2_Click(object sender, System.EventArgs e)
{
  Form f = new child1();
  f.MdiParent = this;
  f.Show();
}

private void showChild1_Click(object sender, System.EventArgs e)
{
  Form f = new child2();
  f.MdiParent = this;
  f.Show();
}

private void formsCount_Click(object sender, System.EventArgs e)
{
  MessageBox.Show(this.MdiChildren.Length.ToString());
  foreach (Form f in this.MdiChildren)
  {
   MessageBox.Show(f.Name.ToString());
  }
}

private void closeAllForms_Click(object sender, System.EventArgs e)
{
  foreach (Form f in this.MdiChildren)
  {
   f.Close();
  }
}

private void exitApplication_Click(object sender, System.EventArgs e)
{
  Application.Exit();
}
}

Now press the F5 key to run the application. You should change the StartUp form in the parent form before starting. When the application is running, click the Show Child1 and Show Child2 menu items a few times each. You should see something like Figure 3.14.

Figure 3.14Figure 3.14 Multiple MDIChildren open in an MDIParent form.

Each time you set the variable f to a new instance of a form, you're setting the MdiParent property to the current form. This makes it an MdiChild. The code for determining the number of MdiChildren open is simply the Length property of the MdiChildren class. Because the form is an object, you can use the For Each method to iterate through its collection to retrieve properties, methods, and events. So, by using the For Each method and calling the form's Close method, you're firing the Form_Closing method of each active form.

To exit the application, you called the Application.Exit() method. The Application object is similar to the App object in Visual Basic 6; it contains information about the current running application. It's important to note that the Closing event won't fire when you call the Application.Exit() method. So, make sure that you gracefully close your windows, and then call Application.Exit(). The code in the closeAllForms click event demonstrates the correct way to accomplish that.

Table 3.3 has some common properties of the Application object, and Table 3.4 has some common methods of the Application object that you'll find useful.

Table 3.3 Useful Application Object Properties

Property

Description

AllowQuit

Gets a value indicating whether the caller can quit this application

CommonAppDataPath

Gets the path for the application data that's shared among all users

CommonAppDataRegistry

Gets the Registry key for the application data that's shared among all users

CompanyName

Gets the company name associated with the application

CurrentCulture

Gets or sets the culture information for the current thread

ExecutablePath

Gets the path for the executable file that started the application

LocalUserAppDataPath

Gets the path for the application data of a local, nonroaming user

ProductName

Gets the product name associated with this application

ProductVersion

Gets the product version associated with this application

StartupPath

Gets the path for the executable file that started the application

UserAppDataPath

Gets the path for the application data of a roaming user

UserAppDataRegistry

Gets the Registry key of the application data specific to the roaming user


Table 3.4 Useful Methods of the Application Object

Method

Description

AddMessageFilter

Adds a message filter to monitor Windows messages as they're routed to their destinations

DoEvents

Processes all Windows messages currently in the message queue

Exit

Informs all message pumps that they must terminate, and then closes all application windows after the messages have been processed

ExitThread

Exits the message loop on the current thread and closes all windows on the thread

OnThreadException

Raises the ThreadException event

RemoveMessageFilter

Removes a message filter from the message pump of the application

Run

Overloaded; begins running a standard application message loop on the current thread


InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020